/*
 * yauosk - Yet Another Useless Operating System Kernel
 *
 * Copyright (c) 2009-2010 Matteo Cicuttin
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _ASM_H_
#define _ASM_H_

#include <sys/types.h>

static __inline uchar
inb(int port)
{
	uchar data;
	__asm __volatile("inb %w1,%0" : "=a" (data) : "d" (port));
	return data;
}

static __inline uint
inl(int port)
{
	uint data;
	__asm __volatile("inl %w1,%0" : "=a" (data) : "d" (port));
	return data;
}

static __inline void
insl(int port, void *addr, int cnt)
{
	__asm __volatile("cld\n\trepne\n\tinsl"     :
					 "=D" (addr), "=c" (cnt)    :
					 "d" (port), "0" (addr), "1" (cnt)  :
					 "memory", "cc");
}

static __inline void
outb(int port, uchar data)
{
	__asm __volatile("outb %0,%w1" : : "a" (data), "d" (port));
}

static __inline void
outw(int port, ushort data)
{
	__asm __volatile("outw %0,%w1" : : "a" (data), "d" (port));
}

static __inline void
outl(int port, uint data)
{
	__asm __volatile("outl %0,%w1" : : "a" (data), "d" (port));
}

static __inline void
outsl(int port, const void *addr, int cnt)
{
	__asm __volatile("cld\n\trepne\n\toutsl"    :
					 "=S" (addr), "=c" (cnt)    :
					 "d" (port), "0" (addr), "1" (cnt)  :
					 "cc");
}

struct gatedesc;
static __inline void
load_idt(struct gatedesc *p, int size)
{
	volatile ushort pd[3];
	
	pd[0] = size-1;
	pd[1] = (uint)p;
	pd[2] = (uint)p >> 16;
	
	asm volatile("lidt (%0)" : : "g" (pd));
}

struct segdesc;
static __inline void
lgdt(struct segdesc *p, int size)
{
	volatile ushort pd[3];
	
	pd[0] = size-1;
	pd[1] = (uint)p;
	pd[2] = (uint)p >> 16;
	
	asm volatile("lgdt (%0)" : : "g" (pd));
}

static __inline void
ltr(ushort sel)
{
	__asm __volatile("ltr %0" : : "r" (sel));
}

static __inline uint
read_eflags(void)
{
	uint eflags;
	__asm __volatile("pushfl; popl %0" : "=r" (eflags));
	return eflags;
}

static __inline void
write_eflags(uint eflags)
{
	__asm __volatile("pushl %0; popfl" : : "r" (eflags));
}

static __inline void
cpuid(uint info, uint *eaxp, uint *ebxp, uint *ecxp, uint *edxp)
{
	uint eax, ebx, ecx, edx;
	asm volatile("cpuid" :
				 "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) :
				 "a" (info));
	if(eaxp)
		*eaxp = eax;
	if(ebxp)
		*ebxp = ebx;
	if(ecxp)
		*ecxp = ecx;
	if(edxp)
		*edxp = edx;
}

static __inline uint
cmpxchg(uint oldval, uint newval, volatile uint* lock_addr)
{
	uint result;
	__asm__ __volatile__("lock; cmpxchgl %2, %0" :
						 "+m" (*lock_addr), "=a" (result) :
						 "r"(newval), "1"(oldval) :
						 "cc");
	return result;
}

static __inline void
cli(void)
{
	__asm__ volatile("cli");
}

static __inline void
sti(void)
{
	__asm__ volatile("sti");
}

#endif /* _ASM_H_ */

